Patient interface for ophthalmologic diagnostic and interventional procedures

ABSTRACT

One embodiment is directed to a patient interface system for ophthalmic intervention on an eye of a patient, comprising: a housing; an optical lens coupled to the housing and having a focal axis; a eye surface engagement assembly coupled to the housing and comprising an inner seal having an inner seal diameter and being configured to circumferentially engage the eye, an outer seal having an outer seal diameter and being configured to circumferentially engage the eye, and a tissue migration bolster structure configured to be positioned circumferentially between the inner and outer circumferential seals and to prevent migration of tissue of the eye toward the eye surface engagement assembly when a vacuum load is applied within the assembly to cause vacuum engagement of the inner and outer seals against the eye.

The present application is a continuation of U.S. application Ser. No.14/602,496, filed on Jan. 22, 2015, which is a continuation of U.S.patent application Ser. No. 13/279,126, filed on Oct. 21, 2011, entitled“PATIENT INTERFACE FOR OPHTHALMOLOGIC DIAGNOSTIC AND INTERVENTIONALPROCEDURES.”

FIELD OF THE INVENTION

The present invention relates to ophthalmic surgical procedures andsystems.

BACKGROUND

Cataract extraction is one of the most commonly performed surgicalprocedures in the world with approximately 4 million cases performedannually in the United States and 15 million cases worldwide. Thismarket is composed of various segments including intraocular lenses forimplantation, viscoelastic polymers to facilitate surgical maneuvers,disposable instrumentation including ultrasonic phacoemulsificationtips, tubing, and various knives and forceps. Modern cataract surgery istypically performed using a technique termed “phacoemulsification” inwhich an ultrasonic tip with an associated water stream for coolingpurposes is used to sculpt the relatively hard nucleus of the lens aftercreation of an opening in the anterior lens capsule termed “anteriorcapsulotomy” or more recently “capsulorhexis”. Following these steps aswell as removal of residual softer lens cortex by aspiration methodswithout fragmentation, a synthetic foldable intraocular lens, or “IOL”,may be inserted into the eye through a small incision.

One of the earliest and most critical steps in the procedure is thecreation, or performance, of capsulorhexis. This step evolved from anearlier technique termed “can-opener capsulotomy” in which a sharpneedle was used to perforate the anterior lens capsule in a circularfashion followed by the removal of a circular fragment of lens capsuletypically in the range of 5-8 mm in diameter. This facilitated the nextstep of nuclear sculpting by phacoemulsification. Due to a variety ofcomplications associated with variations of the can-opener technique,attempts were made by leading experts in the field to develop a bettertechnique for removal of the anterior lens capsule preceding theemulsification step. The concept of the capsulorhexis is to provide asmooth continuous circular opening through which not only thephacoemulsification of the nucleus can be performed safely and easily,but also for easy insertion of the intraocular lens. It provides both aclear central access for insertion, a permanent aperture fortransmission of the image to the retina by the patient, and also asupport of the IOL inside the remaining capsule that would limit thepotential for dislocation.

More modern techniques, such as those employing lasers to assist withthe creation of precision capsulorhexis geometries as well as otherdesired incisions, such as tissue structure relaxing incisions ofvarious types, are disclosed, for example, in U.S. patent applicationSer. Nos. 11/328,970, 12/510,148, 12/048,182, 12/048,185, 12/702,242,12/048,186, 61/289,837, 61/293,357, 61/297,624, and 61/302,437, each ofwhich is incorporated by reference herein in its entirety. Each of thesetechnologies generally requires a patient interface—a structure to jointhe patient's eye and the laser and associated imaging systems, and tooptimize the interaction between the diagnostic and imaging technologiesand the pertinent patient tissue structures. There is a need for furtheroptimization of the patient interface options to advance the standard ofcare of the cataract patient.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates one embodiment of a diagnostic/interventionalophthalmic system.

FIGS. 2A-2C illustrate aspects of patient interface configurationsfeaturing a focusing lens engaged adjacent a cornea of a patient.

FIGS. 3A-3C illustrate aspects of one-piece patient interfaceembodiments.

FIGS. 4A-4E illustrate aspects of two-piece patient interfaceembodiments.

FIGS. 5A-5C illustrate aspects of liquid interface two-piece patientinterface embodiments.

FIGS. 6A-6D illustrate aspects of techniques for utilizingconfigurations such as those described in reference to FIGS. 1-5C.

FIGS. 7A-7V illustrate aspects of a patient interface embodiment thatfeatures a tissue migration bolster structure interposed between twoportions of a sealing structure.

FIG. 8 illustrates aspects of a technique for utilizing configurationssuch as those described in reference to FIGS. 7A-7V.

FIG. 9 illustrates aspects of a technique for utilizing configurationssuch as those described in reference to FIGS. 7A-7V.

FIGS. 10A-10L illustrate aspects of a patient interface embodiment thatfeatures a fidicial configuration selected to assist with in-situ eyeorientation determination.

FIG. 11 illustrates aspects of a technique for utilizing configurationssuch as those described in reference to FIGS. 10A-10L.

FIG. 12 illustrates aspects of a patient interface configuration havingvarious illumination sources associated therewith.

SUMMARY OF THE INVENTION

One embodiment is directed to a patient interface system for ophthalmicintervention on an eye of a patient, comprising: a housing; an opticallens coupled to the housing and having a focal axis; a eye surfaceengagement assembly coupled to the housing and comprising an inner sealhaving an inner seal diameter and being configured to circumferentiallyengage the eye, an outer seal having an outer seal diameter and beingconfigured to circumferentially engage the eye, and a tissue migrationbolster structure configured to be positioned circumferentially betweenthe inner and outer circumferential seals and to prevent migration oftissue of the eye toward the eye surface engagement assembly when avacuum load is applied within the assembly to cause vacuum engagement ofthe inner and outer seals against the eye. The housing may comprise afrustoconical shape having proximal and distal ends and defining asubstantially open volume therebetween. The housing may define a liquidcontainment reservoir when the inner and outer seals are sealablyengaged against the eye and the patient is positioned lying on his back.The eye surface engagement assembly may be configured to be removablycoupled to the eye such that the focal axis of the optical lens issubstantially parallel with a geometric axis of the eye of the patient.The optical lens may have a proximal side and a distal side, the distalside being configured to be interfaced with a surface of the eye, andwherein the distal side has a convex radius of curvature. The convexradius of curvature may be between about 7 mm and about 9 mm. The tissuemigration bolster structure may comprise a spherical surface configuredto be interfaced with the eye of the patient. The tissue migrationbolster structure may define one or more ports configured to allow gasesto pass across the tissue migration bolster structure from a positionimmediately adjacent the eye to a position opposite of the tissuemigration bolster structure from the eye. The one or more ports may havea diameter between about ½ mm and about 2 mm. The system may furthercomprise a pressure equalizing volume fluidly coupling the one or moreports opposite of the tissue migration bolster structure from the eye.The tissue migration bolster structure may be fixedly coupled betweenthe inner and outer seals. The tissue migration bolster structure may beremovably coupled between the inner and outer seals. The tissuemigration bolster structure may comprise a metal selected from the groupconsisting of: aluminum, stainless steel, titanium, and alloys thereof.The tissue migration bolster structure may comprise a polymer selectedfrom the group consisting of: polycarbonate, polyethylene, nylon,polypropylene, isoprene, and copolymers thereof. The inner and outerseals may extend proximally to form inner and outer seal walls that arejoined to a proximal circumferential seal member. A vacuum chamber maybe formed between the inner and outer seal walls and the proximalcircumferential seal member when the seals are engaged with the eye. Thetissue migration bolster structure may be substantially encapsulated bythe vacuum chamber. The inner and outer seal walls may be substantiallycylindrical in shape. The vacuum chamber may have a width definedbetween the outer and inner seal walls, wherein the tissue migrationbolster structure is configured to substantially completely occupy atleast a portion of the width about a circumference of the vacuumchamber. The tissue migration bolster structure may substantially engageboth the outer and inner walls of the base structure about thecircumference of the vacuum chamber. The system may further comprise avacuum source fluidly coupled to the vacuum chamber.

DETAILED DESCRIPTION

As described briefly above, one embodiment of a cataract diagnostic andinterventional system may be implemented by a system that projects orscans an optical beam into a patient's eye (68), such as system (2)shown in FIG. 1 which includes an ultrafast (“UF”) light source ortreatment beam 4 (e.g. a femtosecond laser suitable for creatingdielectric breakdown within a cataractous crystalline lens of an eye).Using this system, a treatment beam may be scanned through a patientinterface and into a patient's eye in three dimensions: X, Y, Z. In thisembodiment, the UF wavelength can vary between about 800 nm and about1100 nm and the pulse width can vary from about 100 fs to about 10picoseconds. The pulse energy of a suitable pulsed treatment beam mayhave a pulse energy of between about 1 microjoule and about 1,000microjoules. The pulse repetition frequency can also vary from about 1kHz to about 250 kHz. Safety limits with regard to unintended damage tonon-targeted tissue bound the upper limit with regard to repetition rateand pulse energy; while threshold energy, time to complete the procedureand stability bound the lower limit for pulse energy and repetitionrate. The peak power of the focused spot in the eye (68) andspecifically within the crystalline lens (69) and anterior capsule ofthe eye is sufficient to produce optical breakdown and initiate aplasma-mediated ablation process. Near-infrared wavelengths arepreferred because linear optical absorption and scattering in biologicaltissue is reduced across that spectral range. As an example, laser (4)may be a repetitively pulsed 1035 nm device that produces 500 fs pulsesat a repetition rate of 100 kHz and an individual pulse energy in theten microjoule range.

The laser (4) is controlled by control electronics (300), via an inputand output device (302), to create optical beam (6). Control electronics(300) may be a computer, microcontroller, etc. In this example, theentire system is controlled by the controller (300), and data movedthrough input/output device IO (302). A graphical user interface GUI(304) may be used to set system operating parameters, process user input(UI) (306) on the GUI (304), and display gathered information such asimages of ocular structures.

The generated UF light beam (6) proceeds towards the patient eye (68)passing through half-wave plate, (8), and linear polarizer, (10). Thepolarization state of the beam can be adjusted so that the desiredamount of light passes through half-wave plate (8) and linear polarizer(10), which together act as a variable attenuator for the UF beam (6).Additionally, the orientation of linear polarizer (10) determines theincident polarization state incident upon beamcombiner (34), therebyoptimizing beamcombiner throughput.

The UF beam proceeds through a shutter (12), aperture (14), and apickoff device (16). The system controlled shutter (12) ensures on/offcontrol of the laser for procedural and safety reasons. The aperturesets an outer useful diameter for the laser beam and the pickoffmonitors the output of the useful beam. The pickoff device (16) includesof a partially reflecting mirror (20) and a detector (18). Pulse energy,average power, or a combination may be measured using detector (18). Theinformation can be used for feedback to the half-wave plate (8) forattenuation and to verify whether the shutter (12) is open or closed. Inaddition, the shutter (12) may have position sensors to provide aredundant state detection.

The beam passes through a beam conditioning stage (22), in which beamparameters such as beam diameter, divergence, circularity, andastigmatism can be modified. In this illustrative example, the beamconditioning stage (22) includes a 2 element beam expanding telescopecomprised of spherical optics (24) and (26) in order to achieve theintended beam size and collimation. Although not illustrated here, ananomorphic or other optical system can be used to achieve the desiredbeam parameters. The factors used to determine these beam parametersinclude the output beam parameters of the laser, the overallmagnification of the system, and the desired numerical aperture (NA) atthe treatment location. In addition, the optical system (22) can be usedto image aperture (14) to a desired location (e.g. the center locationbetween the 2-axis scanning device 50 described below). In this way, theamount of light that makes it through the aperture (14) is assured tomake it through the scanning system. Pickoff device (16) is then areliable measure of the usable light.

After exiting conditioning stage (22), beam (6) reflects off of foldmirrors (28, 30, & 32). These mirrors can be adjustable for alignmentpurposes. The beam (6) is then incident upon beam combiner (34).Beamcombiner (34) reflects the UF beam (6) (and transmits both the OCT114 and aim 202 beams described below). For efficient beamcombineroperation, the angle of incidence is preferably kept below 45 degreesand the polarization where possible of the beams is fixed. For the UFbeam (6), the orientation of linear polarizer (10) provides fixedpolarization.

Following the beam combiner (34), the beam (6) continues onto thez-adjust or Z scan device (40). In this illustrative example thez-adjust includes a Galilean telescope with two lens groups (42 and 44)(each lens group includes one or more lenses). Lens group (42) movesalong the z-axis about the collimation position of the telescope. Inthis way, the focus position of the spot in the patient's eye (68) movesalong the z-axis as indicated. In general there is a fixed linearrelationship between the motion of lens (42) and the motion of thefocus. In this case, the z-adjust telescope has an approximate2.times.beam expansion ratio and a 1:1 relationship of the movement oflens (42) to the movement of the focus. Alternatively, lens group (44)could be moved along the z-axis to actuate the z-adjust, and scan. Thez-adjust is the z-scan device for treatment in the eye (68). It can becontrolled automatically and dynamically by the system and selected tobe independent or to interplay with the X-Y scan device described next.Mirrors (36 and 38) can be used for aligning the optical axis with theaxis of z-adjust device (40). After passing through the z-adjust device(40), the beam (6) is directed to the x-y scan device by mirrors (46 &48). Mirrors (46 & 48) can be adjustable for alignment purposes. X-Yscanning is achieved by the scanning device (50) preferably using twomirrors (52 & 54) under the control of control electronics (300), whichrotate in orthogonal directions using motors, galvanometers, or anyother well known optic moving device. Mirrors (52 & 54) are located nearthe telecentric position of the objective lens (58) and focussing lens(66) combination described below. Tilting these mirrors (52/54) causesthem to deflect beam (6), causing lateral displacements in the plane ofUF focus located in the patient's eye (68). Objective lens (58) may be acomplex multi-element lens element, as shown, and represented by lenses(60, 62, and 64). The complexity of the lens (58) will be dictated bythe scan field size, the focused spot size, the available workingdistance on both the proximal and distal sides of objective 58, as wellas the amount of aberration control. An f-theta lens 58 of focal length60 mm generating a spot size of 10 .mu.m, over a field of 10 mm, with aninput beam size of 15 mm diameter is an example. Alternatively, X-Yscanning by scanner (50) may be achieved by using one or more moveableoptical elements (e.g. lenses, gratings) which also may be controlled bycontrol electronics (300), via input and output device (302).

The aiming and treatment scan patterns can be automatically generated bythe scanner (50) under the control of controller (300). Such patternsmay be comprised of a single spot of light, multiple spots of light, acontinuous pattern of light, multiple continuous patterns of light,and/or any combination of these. In addition, the aiming pattern (usingaim beam 202 described below) need not be identical to the treatmentpattern (using light beam 6), but preferably at least defines itsboundaries in order to assure that the treatment light is delivered onlywithin the desired target area for patient safety. This may be done, forexample, by having the aiming pattern provide an outline of the intendedtreatment pattern. This way the spatial extent of the treatment patternmay be made known to the user, if not the exact locations of theindividual spots themselves, and the scanning thus optimized for speed,efficiency and accuracy. The aiming pattern may also be made to beperceived as blinking in order to further enhance its visibility to theuser.

An optional focussing lens (66), which also may be loosely termed a“contact lens”, which can be any suitable ophthalmic lens, can be usedto help further focus the optical beam (6) into the patient's eye (68)while helping to stabilize eye position. The positioning and characterof optical beam 6 and/or the scan pattern the beam 6 forms on the eye(68) may be further controlled by use of an input device such as ajoystick, or any other appropriate user input device (e.g. GUI 304) toposition the patient and/or the optical system.

The UF laser (4) and controller (300) can be set to target the surfacesof the targeted structures in the eye (68) and ensure that the beam (6)will be focused where appropriate and not unintentionally damagenon-targeted tissue. Imaging modalities and techniques described herein,such as for example, Optical Coherence Tomography (“OCT”), Purkinjeimaging, Scheimpflug imaging, confocal or nonlinear optical microscopy,fluorescence imaging, or ultrasound may be used to determine thelocation and measure the thickness of the lens and lens capsule toprovide greater precision to the laser focusing methods, including 2Dand 3D patterning. Laser focusing may also be accomplished using one ormore methods including direct observation of an aiming beam, OpticalCoherence Tomography, Purkinje imaging, Scheimpflug imaging, confocal ornonlinear optical microscopy, fluorescence imaging, ultrasound, or otherknown ophthalmic or medical imaging modalities and/or combinationsthereof. In the embodiment of FIG. 1, an OCT device (100) is described,although other modalities are within the scope of the present invention.Preferably the OCT imaging device will be configured to measure thecoherence of radiation scattered into an interferometer from structureswithin the “field of view” of the associated beam as it is scanned. AnOCT scan of the eye will provide information about the axial location ofthe anterior and posterior lens capsule, the boundaries of the cataractnucleus, as well as the depth of the anterior chamber. This informationis then be loaded into the control electronics (300), and used toprogram and control the subsequent laser-assisted surgical procedure.The information may also be used to determine a wide variety ofparameters related to the procedure such as, for example, the upper andlower axial limits of the focal planes used for cutting the lens capsuleand segmentation of the lens cortex and nucleus, and the thickness ofthe lens capsule among others.

The OCT device (100) in FIG. 1 includes a broadband or a swept lightsource (102) that is split by a fiber coupler (104) into a reference arm(106) and a sample arm (110). The reference arm (106) includes a module(108) containing a reference reflection along with suitable dispersionand path length compensation. The sample arm (110) of the OCT device(100) has an output connector (112) that serves as an interface to therest of the UF laser system. The return signals from both the referenceand sample arms (106, 110) are then directed by coupler (104) to adetection device (128), which employs either time domain, frequency orsingle point detection techniques. In FIG. 1, a frequency domaintechnique is used with an OCT wavelength of 920 nm and bandwidth of 100nm. Exiting connector (112), the OCT beam (114) is collimated using lens(116). The size of the collimated beam (114) is determined by the focallength of lens (116). The size of the beam (114) is dictated by thedesired NA at the focus in the eye and the magnification of the beamtrain leading to the eye (68). Generally, OCT beam (114) does notrequire as high an NA as the UF beam (6) in the focal plane andtherefore the OCT beam (114) is smaller in diameter than the UF beam (6)at the beamcombiner (34) location. Following collimating lens (116) isaperture (118) which further modifies the resultant NA of the OCT beam(114) at the eye. The diameter of aperture (118) is chosen to optimizeOCT light incident on the target tissue and the strength of the returnsignal. Polarization control element (120), which may be active ordynamic, is used to compensate for polarization state changes which maybe induced by individual differences in corneal birefringence, forexample. Mirrors (122 & 124) are then used to direct the OCT beam 114towards beamcombiners (126 & 34). Mirrors (122 & 124) may be adjustablefor alignment purposes and in particular for overlaying of OCT beam(114) to UF beam (6) subsequent to beamcombiner (34). Similarly,beamcombiner (126) is used to combine the OCT beam (114) with the aimbeam (202) described below. Once combined with the UF beam (6)subsequent to beamcombiner (34), OCT beam (114) follows the same path asUF beam (6) through the rest of the system. In this way, OCT beam (114)is indicative of the location of UF beam (6). OCT beam (114) passesthrough the z-scan 40 and x-y scan (50) devices then the objective lens(58), focussing lens (66) and on into the eye (68). Reflections andscatter off of structures within the eye provide return beams thatretrace back through the optical system, into connector (112), throughcoupler (104), and to OCT detector (128). These return back reflectionsprovide the OCT signals that are in turn interpreted by the system as tothe location in X, Y, Z of UF beam (6) focal location.

OCT device (100) works on the principle of measuring differences inoptical path length between its reference and sample arms. Therefore,passing the OCT through z-adjust 40 does not extend the z-range of OCTsystem (100) because the optical path length does not change as afunction of movement of 42. OCT system (100) has an inherent z-rangethat is related to the detection scheme, and in the case of frequencydomain detection it is specifically related to the spectrometer and theoptical bandwidth of the light source. In the case of OCT system (100)used in FIG. 1, the z-range is approximately 3-5 mm in an aqueousenvironment. Passing the OCT beam (114) in the sample arm through thez-scan of z-adjust (40) allows for optimization of the OCT signalstrength. This is accomplished by focusing the OCT beam (114) onto thetargeted structure while accommodating the extended optical path lengthby commensurately increasing the path within the reference arm (106) ofOCT system (100).

Because of the fundamental differences in the OCT measurement withrespect to the UF focus device due to influences such as immersionindex, refraction, and aberration, both chromatic and monochromatic,care must be taken in analyzing the OCT signal with respect to the UFbeam focal location. A calibration or registration procedure as afunction of X, Y Z should be conducted in order to match the OCT signalinformation to the UF focus location and also to the relate to absolutedimensional quantities.

Observation of an aim beam may also be used to assist the user todirecting the UF laser focus. Additionally, an aim beam visible to theunaided eye in lieu of the infrared OCT and UF beams can be helpful withalignment provided the aim beam accurately represents the infrared beamparameters. An aim subsystem (200) is employed in the configurationshown in FIG. 1. The aim beam (202) is generated by an aim beam lightsource (201), such as a helium-neon laser operating at a wavelength of633 nm. Alternatively a laser diode in the 630-650 nm range could beused. The advantage of using the helium neon 633 nm beam is its longcoherence length, which would enable the use of the aim path as a laserunequal path interferometer (LUPI) to measure the optical quality of thebeam train, for example. Once the aim beam light source generates aimbeam (202), the aim beam (202) is collimated using lens (204). The sizeof the collimated beam is determined by the focal length of lens (204).The size of the aim beam (202) is dictated by the desired NA at thefocus in the eye and the magnification of the beam train leading to theeye (68). Generally, aim beam (202) should have close to the same NA asUF beam (6) in the focal plane and therefore aim beam (202) is ofsimilar diameter to the UF beam at the beamcombiner (34) location.Because the aim beam is meant to stand-in for the UF beam (6) duringsystem alignment to the target tissue of the eye, much of the aim pathmimics the UF path as described previously. The aim beam (202) proceedsthrough a half-wave plate (206) and linear polarizer (208). Thepolarization state of the aim beam (202) can be adjusted so that thedesired amount of light passes through polarizer (208). Elements 206 &208 therefore act as a variable attenuator for the aim beam (202).Additionally, the orientation of polarizer (208) determines the incidentpolarization state incident upon beamcombiners (126 and 34), therebyfixing the polarization state and allowing for optimization of thebeamcombiners' throughput. Of course, if a semiconductor laser is usedas aim beam light source (200), the drive current can be varied toadjust the optical power. The aim beam (202) proceeds through a shutter(210) and aperture (212). The system controlled shutter (210) provideson/off control of the aim beam (202). The aperture (212) sets an outeruseful diameter for the aim beam (202) and can be adjustedappropriately. A calibration procedure measuring the output of the aimbeam (202) at the eye can be used to set the attenuation of aim beam(202) via control of polarizer (206). The aim beam (202) next passesthrough a beam conditioning device (214). Beam parameters such as beamdiameter, divergence, circularity, and astigmatism can be modified usingone or more well known beaming conditioning optical elements. In thecase of an aim beam (202) emerging from an optical fiber, the beamconditioning device (214) can simply include a beam expanding telescopewith two optical elements (216 and 218) in order to achieve the intendedbeam size and collimation. The final factors used to determine the aimbeam parameters such as degree of collimation are dictated by what isnecessary to match the UF beam (6) and aim beam (202) at the location ofthe eye (68). Chromatic differences can be taken into account byappropriate adjustments of beam conditioning device (214). In addition,the optical system (214) is used to image aperture (212) to a desiredlocation such as a conjugate location of aperture (14). The aim beam(202) next reflects off of fold mirrors (222 & 220), which arepreferably adjustable for alignment registration to UF beam (6)subsequent to beam combiner (34). The aim beam (202) is then incidentupon beam combiner (126) where the aim beam (202) is combined with OCTbeam (114). Beamcombiner (126) reflects the aim beam (202) and transmitsthe OCT beam (114), which allows for efficient operation of thebeamcombining functions at both wavelength ranges. Alternatively, thetransmit and reflect functions of beamcombiner (126) can be reversed andthe configuration inverted. Subsequent to beamcombiner (126), aim beam(202) along with OCT beam (114) is combined with UF beam (6) bybeamcombiner (34).

A device for imaging the target tissue on or within the eye (68) isshown schematically in FIG. 1 as imaging system (71). Imaging systemincludes an image capture device such as a camera (74) and anillumination light source (86) for creating an image of the targettissue. The imaging system (71) gathers images which may be used by thesystem controller (300) for providing pattern centering about or withina predefined structure. The illumination light source (86) for theviewing is generally broadband and incoherent. For example, light source(86) can include multiple LEDs as shown. The wavelength of the viewinglight source (86) is preferably in the range of 700 nm to 750 nm, butcan be anything which is accommodated by the beamcombiner (56), whichcombines the viewing light with the beam path for UF beam (6) and aimbeam (202) (beamcombiner 56 reflects the viewing wavelengths whiletransmitting the OCT and UF wavelengths). Further details regardingpositioning and wavelengths of illumination sources are described belowin reference to FIG. 12. The beamcombiner (56) may partially transmitthe aim wavelength so that the aim beam (202) can be visible to theviewing camera (74). Optional polarization element (84) in front oflight source (86) can be a linear polarizer, a quarter wave plate, ahalf-wave plate or any combination, and is used to optimize signal. Afalse color image as generated by the near infrared wavelength isacceptable. The illumination light from light source (86) is directeddown towards the eye using the same objective lens (58) and focussinglens (66) as the UF and aim beam (6, 202). The light reflected andscattered off of various structures in the eye (68) are collected by thesame lenses (58 & 66) and directed back towards beamcombiner (56).There, the return light is directed back into the viewing path via beamcombiner and mirror (82), and on to camera (74). Camera (74) can be, forexample but not limited to, any silicon based detector array of theappropriately sized format. Video lens (76) forms an image onto thecamera's detector array while optical elements (80 & 78) providepolarization control and wavelength filtering respectively. Aperture oriris (81) provides control of imaging NA and therefore depth of focusand depth of field. A small aperture provides the advantage of largedepth of field which aids in the patient docking procedure.Alternatively, the illumination and camera paths can be switched.Furthermore, aim light source (200) can be made to emit in the infraredwhich would not directly visible, but could be captured and displayedusing imaging system (71). Coarse adjust registration is usually neededso that when the focussing lens (66) comes into contact with the corneaand/or sclera, the targeted structures are in the capture range of theX, Y scan of the system. Therefore a docking procedure is preferred,which preferably takes in account patient motion as the systemapproaches the contact condition (i.e. contact between the patient's eye(68) and the focussing lens (66). The viewing system (71) is configuredso that the depth of focus is large enough such that the patient's eye(68) and other salient features may be seen before the focussing lens(66) makes contact with eye (68). Preferably, a motion control system(70) is integrated into the overall control system (2), and may move thepatient, the system (2) or elements thereof, or both, to achieveaccurate and reliable contact between the focussing, or “contact”, lens(66), the housing thereof, and/or the eye (68). In one embodiment, themotion control system (70) may comprise one or more motors responsive tocontrol inputs from a master input device such as a joystick, buttonset, or computer user interface, to allow an operator to commandmovements of the motion control system (70) to electromechanicallyreposition the system relative to the eye of the patient, who willtypically be resting substantially horizontally on an adjustableoperating table or chair. In another embodiment, the chair or table mayhave one or more controllably movable aspects, such as anelectromechanically movable headrest responsive to inputs at an inputdevice such as a joystick, button set, or computer user interface, whichmay be configured to assist with maneuvering a patient's head and eyerelative to the system (the patient's head may be temporarily coupled tothe headrest using a device such as a strap or brace placed around atleast a portion of the patient's head). In another embodiment, movementof the motion control system (70) or associated patient chair or tablemay be manually enabled, preferably with controllable brakingconfigurations at the movable joints to prevent movement in a “locked”configuration. Furthermore, as described below, vacuum suction subsystemand flange may be incorporated into the system and used to stabilize theinterfacing between the focusing lens (66), pertinent housing thereof,and the eye (68). In one embodiment the physical alignment of the eye(68) relative to other portions of the system (2) via the focussing lens(66) may be accomplished while monitoring the output of the imagingsystem (71), and performed manually or automatically by analyzing theimages produced by imaging system (71) electronically by means ofcontrol electronics (300) via IO (302). Force and/or pressure sensorfeedback may also be used to discern contact, as well as to initiate thevacuum subsystem.

FIG. 2A depicts one embodiment of a focussing lens (66) configurationwherein the distal aspect (178) of the lens (66) is placed into directcontact with the cornea and/or sclera (94) of the eye. The scanned beam(90) exiting the system (88) crosses the proximal surface (176) of thelens (66), passes through the lens (66), exits across the distal surface(178) of the lens (66), crosses the cornea and/or sclera (94), andeventually reaches the crystalline lens (69) to facilitateinterventional steps such as capsulorhexis. A close-up view isillustrated in FIG. 2B, to demonstrate the notion of undesirable cornealfolds (96), which may be associated with excess applanation loads placedupon the cornea with contact lens (66) configurations having arelatively large radii of curvature relative to that of the cornea (insuch cases, relatively large applanation loads may be applied to ensuresurface contact between the lens 66 and the relatively convex shape ofthe cornea and/or sclera 94). We have found that corneal folds (96) candegrade the optical path to the interior of the eye, reducing thereliability of laser interaction with the tissue of the eye. Further, itis also generally desirable to minimize intraocular pressure duringdiagnostic and interventional procedures, and large applanation loadstend to increase intraocular pressure. As a result, in the embodimentsdepicted in FIGS. 3A-3C and 4A-4E, comprise focusing lenses (66) withdistal surface radii of curvature that are substantially close to thatof the typical human cornea, thus substantially mitigating applanationand/or interfacing loads, as described in further detail below.

Referring to FIG. 2C, one embodiment of a patient interface (182), whichmay be referred to as a “one-piece” interface, is shown interfaced witha movable portion (160) of a diagnostic and interventional system suchas that described in reference to FIG. 1, the patient interface (182)comprising an interfacial seal configuration (130), a conical lowerhousing portion (132) which houses a focusing lens (66), and acylindrical upper housing portion (134) with a proximal aspectconfigured to mechanically interface and couple with the movable portion(160) of the diagnostic and interventional system. Preferably, in thedepicted embodiment and other illustrative embodiments that follow, thepatient interface (182) is coupled to the movable portion (160) of thediagnostic and interventional system with a load sensing interface, suchas a platform comprising one or more load cells or load sensors (such asMEMS load sensors available from Honeywell, Inc.) configured to providethe operator with output signals or feedback regarding loads beingapplied at such interface due to coupling with the eye of the patient(i.e., such loads may be monitored since they are representative ofcontact loads applied to the eye of the patient by the patient interfaceassembly 182). This feedback may be presented to the user on GUI (304)by control electronics (300) via IO (302). The presentation is intendedfor the user to interpret in adjusting the directionality of motioncontrol electronics (70) during patient coupling to the system.

FIG. 3A illustrates a similar configuration, with the patient interface(182) removably coupled to the movable portion (160) of a diagnostic andinterventional system. FIG. 3B shows a closer up orthogonal view of apatient interface (182) such as that depicted in FIGS. 2C and 3A. Theproximal aspect of the cylindrical upper housing portion (134) forms ageometric coupling interface (136) configured for removable couplingwith the movable portion (160) of a diagnostic and interventionalsystem. FIG. 3C illustrates a cross sectional view of the embodiment ofFIG. 3B to show the position of the focusing lens (66) within theconical lower housing portion (132) as well as the direct interfacing ofthe distal surface (140) of the lens (66) with the cornea and/or sclera(94), and the cross sectional features of the flexible (in oneembodiment comprising a flexible material such as silicone) eye tissueinterface (130), including a cross-sectionally bi-lobed contact surface(142) that creates a vacuum channel (142) between the two lobes whichmay be utilized to removably couple the interface (130) to the surfaceof the cornea and/or sclera (94) with an applied vacuum condition suchas between about 300 and 600 mm of mercury. In one embodiment, thedistal surface (140) of the lens (66) has a radius of curvature equal toabout 8.3 mm, which is slightly larger than that of the average humancornea, to provide an engagement configuration wherein the distalsurface (140) may be slowly engaged with the cornea at approximately thecenter of the distal surface (140), and then with increased engagementand very slight applanating loads, bubbles and fluids squeezed outwardfrom the center of contact, ultimately resulting in a relatively cleaninterfacing for diagnostic and interventional purposes. The shape of thecornea (94) in the depiction of FIG. 3C is the unloaded (un-applanated)shape, to illustrate that there is an intentional mismatch between thedistal surface (140) and the unloaded corneal shape in the depictedembodiment (in an actual loaded scenario, the surfaces would directlymeet, as described above).

Referring to FIGS. 4A-4E, another embodiment (may be referred to as a“two-piece” embodiment) is depicted, wherein a configuration such asthat shown in FIGS. 2C-3C may be deconstructed or decoupled to providefor convenient hand-manipulated placement (i.e., through the use of alightweight handle 150) of the bottom portion (148) before subsequentcoupling with the top portion (152) and movable portion (160) of adiagnostic and interventional system. Together, the top and bottomportions (152, 148) may comprise a “hollow reservoir housing” whichdefines an interior volume and is configured to be interfaced to the eyeas described herein. The top and bottom portions may be removablycoupled to each other using a vacuum coupling interface, an interferencefit (i.e., press fit) interface, an electromagnetic coupling interface(i.e., wherein a current is applied to enforce a junction, and thecurrent may be turned off to release the junction), a manually-actuatedmechanical interface (i.e., wherein a latch or fitting may be manuallyactuated or moved to enforce a locking or unlocking of the interface),or an electromechanically-actuated mechanical interface (i.e., wherein alatch or fitting may be electromechanically actuated or moved, such asby a solenoid or other actuator, to enforce a locking or unlocking ofthe interface). Referring to FIG. 4A, a patient's face (146) and eye(68) are shown with a bottom portion (148) coupled to the cornea and/orsclera of eye (68) using vacuum loads applied using a vacuum port (154)to bring a flexible interface such as those shown in FIGS. 2C-3C intoreleasable engagement with the cornea and/or sclera. The lower portionshown is FIG. 4A has relatively low mass and low moment of inertia, andmay be manipulated easily by hand into a desired position, after whichvacuum may be applied through the port (154) to create the temporaryengagement. Subsequently, the top portion (152) may be coupled to thebottom portion (148) with a mechanical interfacing (156) that maycomprise a slight interference fit (i.e., such as a snap fit), to forman assembled two-part patient interface (184) which may be coupled to amovable portion (160) of a diagnostic and interventional system, asdescribed above. FIGS. 4C and 4D depict another interfacing embodimentwherein a spring clamp (158) may be utilized to removably couple thebottom portion (148) and top portion (152). FIG. 4D is a cross sectionalview of the embodiment of FIG. 4C. FIG. 4E depicts another interfacingembodiment wherein a rotatable collet type coupling member (162) may beutilized to removably couple the bottom portion (148) and top portion(152), by hand-manipulated rotation of the coupling member (162)relative to the bottom portion (149).

FIGS. 5A-5C depict another two-part patient interface (186) embodiment(this embodiment may be referred to as a liquid interface two-partembodiment), comprising an optical element such as a focusing lenselement (92) similar to those described above (element 66) with theexception that the distal surface (178) of the focusing lens element(92) does not come into direct contact with the surface of the cornea(94) and/or sclera—rather, there is a liquid layer (172) interposedbetween the distal surface (178) of the focusing lens element (92) andthe cornea (94) and/or sclera. The optical element (92) may haveproximal and distal surfaces, and the distal surface may be a convexsurface. In one embodiment, the distal surface of the optical element(92) is directly interfaced (i.e., submerged or directly exposed to)with the liquid layer, leaving the liquid layer as the unifyingconnection between the eye and the optical element (92). In oneembodiment the liquid layer may comprise about 2 cubic centimeters ofliquid. The liquid may comprise a material such as water, saline, oil(such as silicon oil), ophthalmic viscoelastic gel, or perfluorocarbonliquid. In the depicted two-part embodiment, the optical element (92) isfixedly coupled to the top, or proximal, portion (152) of the patientinterface; in another embodiment, the optical element (92) may befixedly coupled to the bottom, or distal, portion (148) of the patientinterface. As shown in FIG. 5A, a conical bottom portion (160) iscoupled to a flexible interface (130) similar to those described abovein reference to the one-part and two-part patient interfaceconfigurations. As with the aforementioned embodiments, the flexibleinterface (130) may comprise a compliant circumferential seal memberwhich may comprise two or more circumferential layers with a vacuumspace interposed therebetween to facilitate vacuum-enforced coupling ofthe seal member against the tissue of the eye (using, for example, avacuum load between about 200 mm mercury and about 600 mm mercury, whichmay be applied or generated using a vacuum device such as a regulatedmechanical vacuum pump). At least one of the circumferential layers mayhave a cross sectional shape that is tapered (i.e., with the smallerportion of the taper more immediately adjacent the eye tissue), and atleast one of the circumferential layers may comprise a shape that is atleast partially spherical (i.e., akin to a slice of a spherical shape).A manual manipulation handle is coupled to the bottom portion (160) toallow for easy coupling of the relatively low mass and inertia bottomportion (160) to the cornea and/or sclera (for example, with couplingretention provided by vacuum through the vacuum port 154) beforeinterfacial (168) engagement of the bottom portion to the top portion(166), which is configured to be removably coupled to a movable portion(160) of a diagnostic and interventional system such as that describedin reference to FIG. 1 (for example, using a mechanical couplinginterface, vacuum, or other removable coupling means). As shown in FIGS.5A-5C, the interfacial engagement (168) preferably is configured suchthat the liquid layer (172) is open to the external environment (i.e.,to the atmospheric pressure configuration of the patient examination oroperating room) such that additional fluid may be added by direct pouror syringe (i.e., through one of the depicted access features 165);similarly, liquid may be poured out of the un-encapsulated environmentby changing the orientation of the patient and/or patient interfacerelative to gravity and pouring the liquid out (i.e., through one of thedepicted access features 165). The access features (165) may compriseone or more vents, ports, windows, or the like which provide directaccess between the volume defined for the liquid layer (172) and thenearby atmosphere. Such a configuration, which may be deemed an “openconfiguration” (as opposed to a closed or encapsulated configurationwherein a volume of liquid may be at least temporarily encapsulatedwithin a tank or other structure) wherein the liquid layer (172) hasimmediate access to the outside environment, is advantageous for severalreasons: a) open allows immediate access to the fluid pooled in thepatient interface as a liquid layer—which allows for easier filling,refilling, and draining; b) open allows for fluid to escape whencoupling a two-part design; without such easy escape, unwantedinterfacial pressures may be built up and/or accumulated; c) open allowsfor gas to more easily escape, and gas typically manifests itself in theliquid layer environment as bubbles, which suboptimally change theoptical scenario (i.e., they distort the treatment beam fidelity, andmay cause opacities or other unwanted optical distortions). FIGS. 5B and5C show two slightly different cross sectional views of the embodimentof FIG. 5A. Referring to FIG. 5B, a liquid layer (172) is showninterposed between the distal surface (178) of the focusing lens (92)and the cornea (94) and/or sclera, which are not in physical contactwith each other. The liquid layer (172) acts as a light-transmissivemedium. In the depicted embodiment, the liquid layer freely floats inthe bottom portion 164 before interfacial (168) coupling of the bottomportion (164) and top portion (166) (i.e., the liquid layer 172 restsdue to gravity in the bottom of the bottom portion 164 after the bottomportion 164 has been coupled to the cornea 94 and/or sclera using thebi-lobed lip portion 144, which may be fed vacuum through the vacuumchannels 170 which are connected to the vacuum port 154 shown in FIG.5C). In one embodiment, the outer diameter of the bi-lobed flexibleseals (144) is about 21 mm, and the inner diameter is about 14.5 mm,leaving about 14 mm of clear aperture available for a broad range ofinterventional laser cutting, including but not limited to cornealincisions such as limbal relaxation cuts, etc. One additional benefit ofthe liquid interface is that the optical characteristics of the lenselement (92) may be optimized without as much regard to the anatomicalfit of the proximal and distal face radii of curvature as with thedirect-contact style lens elements (for example, element 66 above).Further, there is greater freedom of materials selection for thefocusing lens (92). In one embodiment, the focusing lens (92) comprisesan approximately 13 mm thick piece of material commercially availableunder the tradename “BK-7”® from Schott North America, Inc. of Elmsford,N.Y., the lens (92) having an approximately 245 mm convex proximalsurface radius of curvature, and an approximately 68 mm convex proximalsurface radius of curvature. Additionally, the displacement of the lens(92) away from the cornea (94) and/or sclera better facilitates anteriorcorneal and/or scleral surface cutting via laser without lens particlecontamination. OCT imaging, as available, for example, in the systemdescribed in reference to FIG. 1, may be utilized to confirm thedimensions of the fluid gap between the cornea (94) and/or sclera andthe focusing element (92). In one embodiment the liquid or fluid layer(172) comprises saline. In other embodiments, liquids may be specifiedwith customized dispersive, refractive, bubble resisting, and otherqualities.

In another embodiment, the two main temporarily or removably coupleableportions of the patient interface structure (148, 152) may be morepermanently coupled (i.e., either before the procedure, or duringmanufacturing of the parts wherein they by be fixedly coupled to eachother or formed together as one construct), in the form of a “one-piece”liquid-facilitated patient interface, with features identical to thosedescribed above in reference to FIGS. 4A-5C, but without the decouplableinterface between such portions (148, 152).

Referring to FIGS. 6A-6D, various implementation embodiments utilizingconfigurations such as those described above are illustrated. Referringto FIG. 6A, subsequent to preoperative diagnostics and patientpreparation steps (320), a patient may be positioned in a substantiallyhorizontal position for patient interface docking (322) (i.e., due tothe desire to not fight gravity when using a one or two part embodiment;further, in a liquid interface two part embodiment, it is desirable tonot have the liquid spill out of the bottom portion). With the patientinterface coupled to a movable portion of the system (324) (i.e., by amechanical interface coupling, vacuum coupling, etc), the movableportion may be utilized to move the patient interface into a desirableinterfacing position relative to the patient's cornea and/or sclera(326), where the patient interface may be removably coupled to thecornea and/or sclera (for example, using vacuum, or mechanical load orpressure to create a liquid-tight seal which may also serve to stabilizethe eye) (328). With the docking completed, the procedure may beconducted along with intraoperative imaging (330). After completing theprocedure, the patient interface may be decoupled (i.e., by releasingthe vacuum) from the cornea and/or sclera (332).

Referring to FIG. 6B, another embodiment is depicted wherein the firsttwo and last two steps are the same as in the embodiment of FIG. 5A, andthe intermediate steps comprise providing a two-piece patient interfaceconfiguration that is removably couplable to the eye, to itself (i.e.,the two pieces), and proximally to the system (334), removably couplingthe bottom portion to the cornea and/or sclera (336), moving the systeminto a position whereby the top portion, when coupled to the bottomportion, may be easily coupled to the system (338), and coupling the topportion to the system (340).

Referring to FIG. 6C, an embodiment is depicted that is similar to thatof FIG. 6B, with the addition of an intermediary step 342 (i.e., toaccommodate a liquid interface two-part patient interface configuration)of adding liquid (i.e., by pouring it in, injecting it in with asyringe, etc) to the bottom portion after the bottom portion is coupledto the cornea and/or sclera. FIG. 6D illustrates an embodiment similarto that of FIG. 6C, with the exception that the liquid layer may beadded (342) before the bottom portion is fully coupled to the corneaand/or sclera (336). Such a configuration may lead to some leakage offluid between the bottom portion and the cornea and/or sclera andsubsequently into the vacuum system.

Referring to FIGS. 7A-7V, various aspects of another embodiment of atwo-part patient interface configuration are illustrated. Referring toFIG. 7A, a two-part assembly comprising a top portion (166) of a patientinterface housing having features (137) configured to be removablycoupled to a ophthalmic laser intervention and imaging system, such asthat described above in reference to FIG. 1, is depicted removablycoupled to a bottom portion (164) of a patient interface housing that isconfigured to be removably coupleable to both the top portion (166) andthe eye (68) of the patient using a interface member (130) configured tobe directly engaged to a portion of the cornea and/or sclera of thepatient's eye. Also shown is a handle (150) for manipulating the bottomportion (164) directly, as well as two vacuum ports (154, 155) that arepassed through the handle (150) housing. Referring to FIG. 7B, with oneportion of the handle (150) housing removed, vacuum lines (198, 224) canbe seen leading from the vacuum ports (154, 155) to two portions of thepatient interface assembly. As described in further detail below, afirst line (198) passes a vacuum load from the first port (154) to avacuum chamber configured to sealably engage the eye (68) to the patientinterface, while another line (224) passes a vacuum load from the secondport (155) to a coupling engagement interface utilized to maintaincoupling of the top portion (166) of the patient interface housing tothe bottom portion (164). Referring to FIG. 7C, a distal portion (174)of the top portion (166) of the patient interface housing is depicted toillustrate that a reduced diameter is utilized for the vacuum sealcoupling with the proximal aspect of the bottom portion (164) of thepatient interface housing. FIG. 7D illustrates a top view through thetop portion (166) of the patient interface housing with an aperture(180) defined therethrough, through which interventional (i.e., such asa laser as described above) and imaging (i.e., such as an OCT imagingsystem, a Scheimpflug system, direct video, direct photo, infrared,ultrasound, confocal microscopy, nonlinear optical imaging,interferometric ranging and imaging, and the like) systems may directvarious forms of radiation en route to the eye of the patient. In oneembodiment, a so-called “field of view” of an imaging system or imagingdevice, such as an OCT, Scheimpflug, video, photo, infrared, orultrasound may be directed at least in part through the aperture (180),and generally also through an aperture formed through the intercoupledbottom portion (164) of the patient interface housing and an associatedlens, to access the eye of the patient.

Referring to FIG. 7E, with the top portion (166) of the patientinterface housing removed, an upper seating seal (188) is viewable, asis an engagement seal (190) that is configured to engage the distalportion (element 174 of FIG. 7C) of the top portion (166) of the patientinterface housing. The bottom portion (164) of the patient interfacehousing in this embodiment comprises a lower frustoconical portion (194)coupled to an upper cylindrical portion (192). Referring to FIG. 7F,with the upper seating seal (element 188 in FIG. 7E) removed, a sealaccommodating feature (196) or trough is shown in the top of the uppercylindrical portion (192). Referring to FIG. 7G, with the uppercylindrical portion (element 192 of FIG. 7F) removed, the engagementseal (190) can be better visualized, as well as the coupling interfacefor the upper cylindrical portion (element 192 of FIG. 7F) and a vacuumdistribution ring (228) configured to transfer a vacuum load from thesecond vacuum line (224) to the mechanical interface with the bottomportion (164) of the patient interface to cause vacuum-stabilizedcoupling of the bottom and top portions (164, 166) of the patientinterface housing members during use. Referring to FIG. 7H, with thevacuum distribution ring (element 228 of FIG. 7G) and the engagementseal (element 190 of FIG. 7G) removed, the weight-saving relief geometry(232) of the inside of the lower frustoconical portion (194) is shown,essentially comprising a series of relief features cut into the walls ofthis structure to save weight. An outline is shown to illustrate anaccess aperture (230) defined through the lower frustoconical portion(194), which continues the access to the eye described above inreference to the aperture (180) through the upper portion (166) of thepatient interface housing through which imaging and interventionradiation of various types may be passed. FIG. 7I further illustratesthis access to the tissue of the eye (68), and also illustrates threefluid access ports (234) through which water or other fluids, asdescribed above in reference to FIGS. 5A-5C, may be added or removed(i.e., removed by pouring off with re-orientation of the head of thepatient relative to gravity down).

FIG. 7J illustrates a further disassembled view depicting the engagementassembly (130) configured to seal the patient interface to the corneaand/or sclera of the eye (68) of the patient using a bi-lobed sealingconfiguration with a vacuum load. As shown in FIG. 7J, the vacuum loadfrom the first vacuum port (154) may be passed through the first vacuumlead (198), across a lumen defined through a portion of the lowerfrustoconical portion (element 194 of FIG. 7I) shown here in dashedlines (236), and into a vacuum port (238) on the engagement assembly(130). Referring to FIG. 7K, a cross sectional view is depicted to showthat the vacuum load may be passed through the vacuum port (238) andinto a vacuum chamber defined as a captured volume between the inner andouter seals, the corneal and/or scleral tissue of the eye (68) of thepatient, and the proximal circumferential seal member portion (131) ofthe engagement assembly (130) that joins the inner seal (240) to theouter seal (242) by virtue of a substantially cylindrical inner sealwall (282) and a substantially cylindrical outer seal wall (284). Alsoshown in FIG. 7K is a tissue migration bolster structure (246)substantially encapsulated within the vacuum chamber and configured tobe positioned circumferentially between the inner and outer seals (240,242) and to prevent localized migration, or distension, of the tissue ofthe eye (68) toward the patient interface assembly when a vacuum load isapplied and transferred into the vacuum chamber. In other words, thetissue migration bolster structure (246) is configured to form a barrierto block distension of the involved ring of eye tissue when a vacuumload is applied. We have found that with such a structure (246), we areable to apply vacuum loads to enforce coupling of the patient interfaceassembly to the eye of the patient between about 100 mm and about 500 mmof mercury without unacceptable distension. As described above relativeto configurations without this structural element, significantly lowercoupling loads are desired to prevent localized distension. Also shownin FIG. 7K is a pressure equalization volume (244) comprising a volumeof free space positioned between a tissue migration bolster structure(246) and the proximal circumferential seal member portion (131) of theengagement assembly (130), which is configured to allow for the flow ofgases (i.e., such as air or nitrogen) to distribute and equalize thepressure within each of a series of ports (elements 254 in FIG. 7O, forexample) as they are fluidly coupled to the vacuum port (238) by suchequalization volume (244). FIG. 7L illustrates a similar view as FIG.7J, with a different orientation to better show the pressureequalization volume (244), and FIGS. 7M and 7N shown further magnifiedviews. In the depicted embodiment, at least a portion of the tissuemigration bolster structure (246) substantially fills the width of thevacuum chamber between the inner seal wall (282) and the outer seal wall(284) to form a sealing interface between the equalization volume (244)and the surface of the eye (68). In one embodiment the tissue migrationbolster structure (246) is fixedly coupled between the inner seal wall(282) and the outer seal wall (284); in another embodiment it is pressfit in between the inner seal wall (282) and the outer seal wall (284);in another embodiment, it is loosely fit in between the inner seal wall(282) and the outer seal wall (284), in which case there is not asealing interface between the equalization volume (244) and the surfaceof the eye (68). Preferably the portion of the tissue migration bolsterstructure (246) that becomes directly engaged with the tissue of the eye(68) forms a spherical surface (248), an in the aggregate, the surfacesof the patient interface assembly directly engaging the tissue of theeye (68) preferably form a spherical aggregate surface that hassubstantially the same profile as the surface of the eye anatomy, whichis generally substantially spherical.

Referring to FIGS. 7O-7V, various aspects of an embodiment of a tissuemigration bolster structure are shown in detail without other devicehardware engaged. Referring to FIG. 7O, a tissue migration bolsterstructure (246) is shown engaged with the tissue of an eye (68). A portrelief feature (250) is formed to accommodate flow of gases (i.e., air,nitrogen, or the like) in through the port (element 238 of FIG. 7N, forexample) to the equalization volume (element 244 of FIG. 7N). Further,orientation confirmation feature (252) is shown which is configured toassist a device assembler to place the tissue migration bolsterstructure (246) in the correct orientation relative to the port (element238 of FIG. 7N, for example). A plurality of vents or ports (254) isshown connecting the region of the equalization volume (element 244 ofFIG. 7N) to the surface of the eye (68). These small ports, havingdiameters between about ½ mm and about 2 mm, expose the eye (68) to thevacuum load on a distributed basis, with the substantially sphericalengagement surface there to prevent distension that could result withoutthe bolster structure. FIG. 7P illustrates a view similar to that ofFIG. 7O, but at a different orientation. FIG. 7Q shows a close-up viewsimilar to that of FIG. 7P. FIG. 7R shows a close-up view depicting witha dashed arrow (256) the path of vacuum access from the region of theequalization volume (element 244 of FIG. 7N), through the depicted port(254) to the surface of the eye (68). FIGS. 7S and 7T show orthogonalviews of the depicted embodiment of the tissue migration bolsterstructure (246), and FIGS. 7U and 7V show cross sectional views of thedepicted embodiment of the tissue migration bolster structure (246).Suitable tissue migration bolster structures (246) may comprise metallicmaterials, such as aluminum, stainless steel, titanium, and alloysthereof or polymers selected from the group consisting of:polycarbonate, polyethylene, nylon, polypropylene, isoprene, andcopolymers thereof.

Referring to FIG. 8, a technique for utilizing a system such as thatdescribed herein in reference to FIGS. 7A-7V is illustrated. As shown inFIG. 8, subsequent to preoperative diagnostics and patient preparationsteps (320), a patient may be positioned in a substantially horizontalposition for patient interface docking (322) (i.e., due to the desire tonot fight gravity when using a one or two part embodiment; further, in aliquid interface two part embodiment, it is desirable to not have theliquid spill out of the bottom portion). The top portion of the patientinterface may be coupled to a movable portion of the system (334) (i.e.,by a mechanical interface coupling, vacuum coupling, etc). The lowerportion of the patient interface may be removably coupled to the corneaand/or sclera, and this coupling may be enforced with a vacuum load,while a mechanical feature of the lower portion of the patient interfacephysically limits the amount of distension of the immediately associatedportion of the eye toward the patient interface (344). With the dockingcompleted, in a two part liquid configuration, fluid may be added to thebottom portion of the patient interface housing to place the surface ofthe eye within fluid connection to the lens element coupled to theinside of the bottom portion of the patient interface housing (342). Themovable portion of the system may be utilized to move (338) the topportion of the patient interface into a position wherein the top andbottom portions of the patient interface may be intercoupled (thejunction being enforced, for example, with another vacuum load) (340).The procedure may be conducted along with intraoperative imaging usingsystems such as confocal microscopy, nonlinear optical imaging,interferometric ranging and imaging, OCT, infrared, light photography,light video, infrared photography or video, ultrasound, Scheimpflug, andthe like (330). After completing the procedure, the patient interfacemay be decoupled (i.e., by releasing the vacuum) from the cornea and/orsclera (332).

FIG. 9 illustrates an embodiment similar to that of FIG. 8, with theexception that the liquid layer may be added (342) before the bottomportion is fully coupled to the cornea and/or sclera (344). Such aconfiguration may lead to some leakage of fluid between the bottomportion and the cornea and/or sclera and subsequently into the vacuumsystem.

Referring to FIGS. 10A-10L, various embodiments are shown that may beutilized to assist with the intraoperative determination of eyeorientation relative to the instrumentation based upon temporarily marksinitially created by a healthcare provider during preparation for anintervention. Conventionally, the provider will conduct a preoperativeexamination with the patient in an upright position, and will make aseries of marks with a pen upon the cornea and/or sclera to provide atemporary reference with regard to the astigmatic axis of the subjecteye; this axis may be subsequently utilized during surgery to placerelaxing cuts, radial cuts, or other types of incisions, to tailor thegeometry of capsular cuts, etc. One of the challenges is that when thepatient goes from the upright preoperative environment to being flat onthe surface of an operating table during the invention, somere-orientation of the eye is common relative to the position/orientationof the cranium, for example, and the surgeon must find a way tore-establish his understanding of the orientation of the eye anatomyrelative to the interventional tools. In one embodiment, a series offidicual features and/or markers placed within the field of view of theimaging system utilized to view the eye anatomy may be used to establishthe eye orientation.

Referring to FIG. 10A, with a patient interface assembly intercoupledbetween an eye of a patient (68) and an interventional system such asthat (2) shown in FIG. 1, the imaging subsystem may be configured tohave a field of view directed through the aperture (180, 230) of thepatient interface housing (166, 164), across the lens element (not shownin FIG. 10A; see element 92 of FIGS. 5B and 5C, for example), throughany associated fluid (not shown in FIG. 10A; see element 172 of FIGS. 5Band 5C, for example), to the surface of the eye (68) and into the eye.FIG. 10B shows a similar view with the top portion of the patientinterface housing (166) removed. FIG. 10C shows a closer view witharrows pointing out the location of the inner seal (240) relative to theeye (68), and also the locations of three fiducial markers (258, 260,262) that are coupled to, defined by, or formed within the lowerfrustoconical portion (194) of the patient interface housing. FIG. 10Dshows another view at a different orientation, and FIG. 10E shows aclose-up view of one of the fiducial features (260), which in thisembodiment represents a prominent step that has X (266), Y (268), and Z(270) dimensions that are configured to be easily picked up by theassociated imaging system. For example, in a configuration featuring anOCT imaging system, dimensions of X and Y that are about 1 mm, and Zthat is about ½ mm provide for a fidicial that are easily detectable bythe imaging system. As described below in reference to FIG. 11, eyeorientation relative to the interventional system based upon anastigmatic or other predetermined axis may be determinedintraoperatively if two or more fiducials on the patient interface areplaced into some predetermined orientation relative to thepreoperatively created marks that are associated with the astigmatic orother predetermined axis. Thus a requisite element of suchintraoperative feature set is one or more fiducials coupled to orresident on the patient interface that are within the field of view ordetection by the imaging subsystem. FIGS. 10F-10L illustrate severalvariations.

Referring to FIG. 10F, a diagrammatic representation of an inner annulusformed by the distal end of a lower patient interface portion (194) isdepicted with a plurality of prominent step fiducials (264) associatedtherewith, as in the embodiment of FIG. 10C, for example. Two of thesefiducials (264) may be manually lined up with the marks (286, 288) thathave been manually created preoperatively on the surface of the eye (forexample, using a marking pen). One of the challenges is that markscreated with marking pens tend to be washed away by the activity of theeye, eyelid, and tears/saline, and thus it is valuable to utilize themto “register” the position and/or orientation of the patient interfacerelative to the anatomy of the eye, and temporarily fix thisrelationship with the vacuum or other means, before too much time haselapsed after the time that the marks are created (i.e., before themarks have become too washed away or diffuse to see precisely).Typically the patient care provider will not only want to understand theorientation of the eye relative to the distal system portions (element160 of FIG. 2C, for example), but will also want to have a geometricaxis of the eye substantially aligned with a focal axis of the opticallens housed within the patient interface assembly (typically the focalaxis of the optical lens will be aligned to pass through theviewing/treatment aperture of the patient interface housing); indeed, itis desirable to have the geometric axis of the eye directed in adirection approximately parallel to a gravitational force vector whenthe patient is lying down approximately flat (in other words, have thepatient flat and the eye directed “straight up”).

In another embodiment, small removable pins or trocar members, such asthose commonly used by retinal surgeons and available from supplierssuch as the Grieshaber division of Alcon Corporation, may be utilized asmarkers—or as fiducials themselves—to assist with registering thepatient interface to the anatomy from an orientation and/or positionperspective. The additional fiducial of the embodiment of FIG. 10F mayprovide further information regarding which side is “up” from anorientation perspective, but is not absolutely necessary for orientationregistration (i.e., two fiducials is functionally adequate for this, asin the embodiment of FIG. 10G, which features two diametrically opposedprominent step fiducials integrated into the lower patient interfaceportion 194).

Referring to FIG. 10H, an embodiment is shown to demonstrate that themarkers and fiducials need not be lined up in a diametrically opposedconfiguration, or in any kind of homogeneous pattern relative to eachother about the portion of the patient interface exposed to the field ofview of the imaging system. The important issue is to understand whatthe predetermined marks (286, 288) mean, and to line these marks up withthe fiducials (264). Although in the depicted embodiment, the fiducials(264) are configured to be directly aligned with the marks (286, 288),in other embodiments these may be misaligned intentionally by a knownoffset, etc. Again, the key is to make sure that the predeterminedinformation regarding astigmatic axis, etc, that is memorialized in themarks gets transferred to the in-situ surgical scenario in terms of theregistration of the patient interface to the anatomy. In other words, ifyou know what you want to do based upon a preoperative surgical plan andsome marks related thereto, you want to make sure that this informationcan be transferred to the in-situ scenario and utilized understandingwhere the diagnostic and interventional system is relative to the actualanatomy.

Referring to FIG. 10I, the fiducials need not be prominent steps, asshown in the aforementioned embodiments; they may be depressed steps(i.e., depressed into the surrounding surface of the patient interface),be formed to include prominent or depressed edges (272), or they maycomprise contrasting patterns viewable by photography, video, orinfrared imaging, for example, as in the “X” pattern visual fiducials(274) of FIG. 10I. FIG. 10J depicts an embodiment with a plurality ofhigh-contrast visual fiducials (276), which may, for example, be blackpainted portions against a white background as shown, white paintedportions against a black background, or the like. Further, the fiducialsmay comprise a material, such as a fluorescing paint or otherfluorescing material, which becomes highly visible in contrast to thesurrounding material when illuminated with the appropriate radiation andviewed with the appropriate imaging device (for example, certain carbontetrachloride solutions fluoresce under infrared radiation and may beimaged with an infrared camera or video camera). FIG. 10K illustrates anembodiment with fluorescing fiducials (278). Further, the geometry ofthe fiducials need not be rectangular, square, or edged—it may be anygeometry that may be easily detected with the particular imaging systemat hand, and different types may be mixed and matched for a particularimplementation. The embodiment of FIG. 10L has four different types offiducials—an edge fiducial (272—may be prominent or depressed relativeto the surrounding surface), a hemispherical fiducial (may be prominentor depressed {i.e., concave or convex} relative to the surroundingsurface), a contrast fiducial (276), and a step fiducial (may beprominent or depressed relative to the surrounding surface). Thus theone or more fiducials may comprise surface irregularities relative toother surrounding surfaces, and/or highly visible or detectable featuresor materials.

Referring to FIG. 11, an implementation utilizing aspects ofconfigurations such as those described in reference to FIGS. 10A-10L isillustrated. As shown in FIG. 11, subsequent to preoperative diagnosticsand patient preparation steps, including creating one or more geometricmarks on the eye (346), a patient may be positioned in a substantiallyhorizontal position for patient interface docking (322) (i.e., due tothe desire to not fight gravity when using a one or two part embodiment;further, in a liquid interface two part embodiment, it is desirable tonot have the liquid spill out of the bottom portion). The top portion ofthe patient interface may be coupled to a movable portion of the systemwhile the bottom portion, containing or comprising two or morefiducials, may remain uncoupled for ease of manual manipulation (348).The lower portion of the patient interface may be removably coupled tothe cornea and/or sclera, and this coupling may be enforced with avacuum load, while a mechanical feature of the lower portion of thepatient interface physically limits the amount of distension of theimmediately associated portion of the eye toward the patient interface(344). With the docking completed, in a two part liquid configuration,fluid may be added to the bottom portion of the patient interfacehousing to place the surface of the eye within fluid connection to thelens element coupled to the inside of the bottom portion of the patientinterface housing (342). The movable portion of the system may beutilized to move (338) the top portion of the patient interface into aposition wherein the top and bottom portions of the patient interfacemay be intercoupled (the junction being enforced, for example, withanother vacuum load) (340). The procedure may be conducted along withintraoperative imaging using systems such as OCT, infrared, lightphotography, light video, infrared photography or video, ultrasound,Scheimpflug, and the like to not only image the subject tissuestructures of the eye, but also to track the positions of the fiducialssuch that the anatomical positioning relative to the imaging device maybe understood (350). After completing the procedure based at least inpart upon the geometric relationship between the fiducials and geometricmarkers (352), the patient interface may be decoupled (i.e., byreleasing the vacuum) from the cornea and/or sclera (332). While theembodiment of FIG. 11 combines aspects of the distension-preventingtechnology described in reference to FIGS. 7A-9, the two-part liquidpatient interface configuration of FIGS. 5A-5C, and the marker-fiducialconfigurations of FIGS. 10A-10L, it is important to emphasize that theseaspects need not all be combined in every embodiment of the invention.For example, in one embodiment, a one-piece or two-piece non-liquidpatient interface configuration may be augmented with a distentionpreventing sealing interface without the configurations for usingmarkers and fiducials to register the anatomy to the imaging system; inanother embodiment, for example, a two part liquid patient interfaceconfiguration may comprise the marker-fiducial features for anatomicregistration without the distention preventing sealing interface. Thetechnology features may be used together in various combinations andpermutations within the scope of the invention.

Referring to FIG. 12, an embodiment similar to that shown in FIG. 5A isdepicted, with the exception that several illumination source (296, 294)options are illustrated. As described above in reference to FIG. 1,various types of light sources are suitable for assisting with image andvideo capture of the subject tissue structures using, for example,conventional camera and video sensors and/or infrared camera and videosensors. Referring again to FIG. 12, in one embodiment, an illuminationsource (294) will be configured to broadcast illumination radiation in afield (298) configuration whereby the illumination radiation is passedthrough the central aperture or passageway of the patient interfaceassembly (168, 164), including through any lens element that may becoupled thereto and positioned across the central aperture, to reachsubstantially the entire surface of the eye (68) of the patient that isaccessible through the patient interface (i.e., the portion of thecornea and/or sclera that is bounded by the inner seal of the engagementassembly 130). In another configuration, also illustrated in FIG. 12,one or more illumination sources (296) may be configured to broadcastillumination radiation in a field (308) configuration whereby theillumination radiation is passed through at least a portion of thepatient interface housing assembly (164, 168) to reach substantially theentire surface of the eye (68) of the patient that is accessible throughthe patient interface (i.e., the portion of the cornea and/or sclerathat is bounded by the inner seal of the engagement assembly 130); withsuch a configuration, depending upon the wavelength of transmittedillumination irradiation, it may be desirable to have one or moreportions of the patient interface assembly (164, 168) comprisesubstantially translucent materials that are selected to pass theillumination irradiation across walls and features of such structuresand in toward the subject surface of the eye (68). FIG. 12 also shows anOCT irradiation and/or scatter/reflection beam (290) being passedthrough the central aperture of the patient interface housing (164,168), and a diagrammatic representation of a scanning/broadcast andscatter/reflection field (292) for this imaging technology, the field(292) being akin to a field of view for such technology. The desiredfield of view of the OCT imaging system preferably includes as much ofthe subject eye (68) tissue as possible given the position of the OCTsource and the surface of the eye (68) of the patient that is accessiblethrough the patient interface (i.e., the portion of the cornea and/orsclera that is bounded by the inner seal of the engagement assembly 130;the OCT may also be able to provide additional data by imaging “through”one or more elements of the patient interface assembly, such as throughthe inner seal 240 as engaged with the eye 68), and, as described above,the OCT may function as a 3-dimensional sensor for monitoring positionsof fiducials which may be coupled to, or formed in, portions of thepatient interface assembly. For example, as described above, the OCT orother imaging sensor may be configured to capture one or more imagesthat feature both the registration fiducials coupled to or formed withinthe patient interface and the geometric markers which may be placed orcreated preoperatively (i.e., with a marker, small removable trocar,etc), and when the patient interface is engaged with the eyeintraoperatively, the geometric relationship between the anatomy of theeye (based upon the geometric markers) and the imaging device may beaccurately characterized when the geometric relationship between thepatient interface and the geometric markers is known (i.e., by virtue oflining the markers up with the fiducials in some quantifiable way). Inother words, with such a configuration, the preoperatively createdgeometric markers, based upon healthcare provider analysis of thepatient's anatomy, establish an axis or other geometric landmark whichmay be mapped to the patient interface in-situ by lining the geometricmarkers up with the fiducials of the patient interface; then with animaging device configured to capture images of both the anatomy and thefiducials together, the geometric relationship between the anatomy andthe imaging device may be determined or characterized with geometrictransformation. In a configuration wherein a two-dimensional imagingdevice is utilized, such as a conventional camera or video system usingvisible or infrared light, an assumption may be made that the fiducialsof the patient interface are substantially co-planar (and, indeed, thefiducials may be specifically configured to be substantially co-planar),and the quantitative analysis may lead to characterizations of positionsand/or movements of the fiducials and associated eye anatomy relative toa plane that is substantially perpendicular to the axis of the apertureof the patient interface through which the imaging device is operated.In an embodiment wherein the imaging device comprises an OCT device,additional information may be derived, since OCT is capable of measuringfully three-dimensional positions of the various structures of interest,such as each of the fiducials and various anatomical features of the eye(68). In other words, the three-dimensional capability of the OCTtechnology works as a depth sensor as well as a position sensor.Although we specifically describe OCT in this scenario, it is to beunderstood that all of the 3-dimensional imaging modalities describedherein may be utilized to provide 3-dimensional position sensing. Thus,in an embodiment wherein OCT is utilized to characterize the geometricrelationship of the fiducials, the imaging device, and the anatomy, thethree dimensional motion of the patient interface may be characterizedin pitch, yaw, and roll as well as X, Y, and Z given updatedthree-dimensional position data regarding each of the fiducials. Suchcalculated information may be utilized to characterize the eye anatomyto which the patient interface may be intercoupled—or may be utilized tosuccessfully dock/engage the patient interface with the surface of theeye before temporarily vacuum locking the two together as describedabove (in other words, the pitch, yaw, roll, x, y, z data for thepatient interface may be utilized to ensure that the patient interfaceis being engaged against the eye in a preferred orientation that is not“cockeyed” relative to the surface of the eye upon engagement, etc).Positional information derived from image or signal analysis of theimage(s) or detection(s) of the patient interface as it is being broughtinto contact with the system via IO (302) and control electronics (300)may be employed to provide guidance to the user. This guidance may inthe form of a visible cue or marker displayed upon GUI (304) that isintended for the user to recognize and manually compensate for using IO(306) to position the patient via UI (306) to control motion controlsystem (70), or similar means. The abovementioned positional informationmay also be used to generate signals that can be utilized by controlelectronics (300) directly to control motion control system (70) inorder to automatically and accurately couple the patient to the system.Information about the axial position of the patient interface, or thesystem member to which it is attached may further be used to judge thedepth location of the patient when using en-face 2-dimensional imagingmeans such as infrared, light photography, light video, and/or infraredphotography or video.

Various exemplary embodiments of the invention are described herein.Reference is made to these examples in a non-limiting sense. They areprovided to illustrate more broadly applicable aspects of the invention.Various changes may be made to the invention described and equivalentsmay be substituted without departing from the true spirit and scope ofthe invention. In addition, many modifications may be made to adapt aparticular situation, material, composition of matter, process, processact(s) or step(s) to the objective(s), spirit or scope of the presentinvention. Further, as will be appreciated by those with skill in theart that each of the individual variations described and illustratedherein has discrete components and features which may be readilyseparated from or combined with the features of any of the other severalembodiments without departing from the scope or spirit of the presentinventions. All such modifications are intended to be within the scopeof claims associated with this disclosure.

Any of the devices described for carrying out the subject diagnostic orinterventional procedures may be provided in packaged combination foruse in executing such interventions. These supply “kits” may furtherinclude instructions for use and be packaged in sterile trays orcontainers as commonly employed for such purposes.

The invention includes methods that may be performed using the subjectdevices. The methods may comprise the act of providing such a suitabledevice. Such provision may be performed by the end user. In other words,the “providing” act merely requires the end user obtain, access,approach, position, set-up, activate, power-up or otherwise act toprovide the requisite device in the subject method. Methods recitedherein may be carried out in any order of the recited events which islogically possible, as well as in the recited order of events.

Exemplary aspects of the invention, together with details regardingmaterial selection and manufacture have been set forth above. As forother details of the present invention, these may be appreciated inconnection with the above-referenced patents and publications as well asgenerally known or appreciated by those with skill in the art. Forexample, one with skill in the art will appreciate that one or morelubricious coatings (e.g., hydrophilic polymers such aspolyvinylpyrrolidone-based compositions, fluoropolymers such astetrafluoroethylene, hydrophilic gel or silicones) may be used inconnection with various portions of the devices, such as relativelylarge interfacial surfaces of movably coupled parts, if desired, forexample, to facilitate low friction manipulation or advancement of suchobjects relative to other portions of the instrumentation or nearbytissue structures. The same may hold true with respect to method-basedaspects of the invention in terms of additional acts as commonly orlogically employed.

In addition, though the invention has been described in reference toseveral examples optionally incorporating various features, theinvention is not to be limited to that which is described or indicatedas contemplated with respect to each variation of the invention. Variouschanges may be made to the invention described and equivalents (whetherrecited herein or not included for the sake of some brevity) may besubstituted without departing from the true spirit and scope of theinvention. In addition, where a range of values is provided, it isunderstood that every intervening value, between the upper and lowerlimit of that range and any other stated or intervening value in thatstated range, is encompassed within the invention.

Also, it is contemplated that any optional feature of the inventivevariations described may be set forth and claimed independently, or incombination with any one or more of the features described herein.Reference to a singular item, includes the possibility that there areplural of the same items present. More specifically, as used herein andin claims associated hereto, the singular forms “a,” “an,” “said,” and“the” include plural referents unless the specifically stated otherwise.In other words, use of the articles allow for “at least one” of thesubject item in the description above as well as claims associated withthis disclosure. It is further noted that such claims may be drafted toexclude any optional element. As such, this statement is intended toserve as antecedent basis for use of such exclusive terminology as“solely,” “only” and the like in connection with the recitation of claimelements, or use of a “negative” limitation.

Without the use of such exclusive terminology, the term “comprising” inclaims associated with this disclosure shall allow for the inclusion ofany additional element—irrespective of whether a given number ofelements are enumerated in such claims, or the addition of a featurecould be regarded as transforming the nature of an element set forth insuch claims. Except as specifically defined herein, all technical andscientific terms used herein are to be given as broad a commonlyunderstood meaning as possible while maintaining claim validity.

The breadth of the present invention is not to be limited to theexamples provided and/or the subject specification, but rather only bythe scope of claim language associated with this disclosure.

The invention claimed is:
 1. A patient interface system for interfacingan ophthalmic intervention system with an eye of a patient, comprising:a housing, the housing defining a central axis; an optical lens coupledto the housing; an eye surface engagement assembly coupled to thehousing and comprising an inner seal having an inner seal diameter andbeing configured to circumferentially engage the eye, an outer sealhaving an outer seal diameter and being configured to circumferentiallyengage the eye, a vacuum chamber being defined by the eye surfaceengagement assembly and between the inner and outer seals; and a ringshaped tissue migration bolster structure positioned circumferentiallybetween the inner and outer circumferential seals and at least partiallywithin the vacuum chamber, the tissue migration bolster structure havinga distal surface configured to contact the eye, the tissue migrationbolster structure defining a plurality of ports spaced apart form eachother in an angular direction with respect to the central axis, eachport being a recess from the distal surface and extending in a radialdirection with respect to the central axis.
 2. The system of claim 1,wherein the housing comprises a frustoconical shape having proximal anddistal ends and defining a substantially open volume therebetween. 3.The system of claim 1, wherein the housing defines a liquid containmentreservoir when the inner and outer seals are sealably engaged againstthe eye and the patient is positioned lying on his back.
 4. The systemof claim 1, wherein the eye surface engagement assembly is configured tobe removably coupled to the eye such that a focal axis of the opticallens is substantially parallel with a geometric axis of the eye of thepatient.
 5. The system of claim 1, wherein the optical lens has aproximal side and a distal side, the distal side being configured to beinterfaced with a surface of the eye, and wherein the distal side has aconvex radius of curvature.
 6. The system of claim 5, wherein the convexradius of curvature is between 7 mm and 9 mm.
 7. The system of claim 1,wherein the distal surface of the tissue migration bolster structurecomprises a spherical surface.
 8. The system of claim 1, wherein theports configured to allow gases to pass across the tissue migrationbolster structure from a position immediately adjacent the eye to aposition opposite of the tissue migration bolster structure from theeye.
 9. The system of claim 8, wherein the one or more ports have adiameter between ½ mm and 2 mm.
 10. The system of claim 8, furthercomprising a pressure equalizing volume fluidly coupling the one or moreports opposite of the tissue migration bolster structure from the eye.11. The system of claim 1, wherein the tissue migration bolsterstructure is fixedly coupled between the inner and outer seals.
 12. Thesystem of claim 1, wherein the tissue migration bolster structure isremovably coupled between the inner and outer seals.
 13. The system ofclaim 1, wherein the tissue migration bolster structure comprises ametal selected from the group consisting of: aluminum, stainless steel,titanium, and alloys thereof.
 14. The system of claim 1, wherein thetissue migration bolster structure comprises a polymer selected from thegroup consisting of: polycarbonate, polyethylene, nylon, polypropylene,isoprene, and copolymers thereof.
 15. The system of claim 1, wherein theinner and outer seals extend proximally to form inner and outer sealwalls that are joined to a proximal circumferential seal member.
 16. Thesystem of claim 15, wherein the tissue migration bolster structure hasan orientation confirmation feature configured to register with theproximal circumferential seal member and ensure correct angularorientation of the tissue migration bolster structure relative thereto.17. The system of claim 15, further comprising a vacuum source fluidlycoupled to the vacuum chamber, and the tissue migration bolsterstructure has a vacuum port that registers with a vacuum source inletthrough the proximal circumferential seal member when the orientationconfirmation feature is registered with the proximal circumferentialseal member.
 18. The system of claim 15, wherein the inner and outerseal walls are substantially cylindrical in shape.
 19. The system ofclaim 15, wherein the vacuum chamber has a width defined between theouter and inner seal walls, wherein the tissue migration bolsterstructure is configured to occupy at least a portion of the width of acircumference within the vacuum chamber.
 20. The system of claim 19,wherein the tissue migration bolster structure substantially engagesboth the outer and inner walls of a base structure around thecircumference of the vacuum chamber.